The invention relates to the filtering of liquids and, more particularly to an apparatus for the pressure injection of gas, usually air, into a pressure filtration cell.
In the case of customary pressure filtration cells, compressed gas is forced into the top of a container cell by way of a non-return valve. The gas thus enters a pressure gas chamber of the pressure filtration cell above the liquid that is to be filtered. Pressure build-up in the cell above the liquid forces the liquid through a filter located at an outlet of the cell. Sources of compressed gas have heretofore comprised compressed gas cylinders with constant, or at least practically constant, gas pressure. In order to control the dynamic filtration conditions on the filter surface and in the medium to be filtered, a magnet stirrer can be fixed in the cell freely rotatably above the filter surface. This stirrer is situated on a long shaft mounted at the lid or dome of the pressure filtration cell. The magnetic stirrer is turned by a rotating guide magnet disposed below the cell to mix the liquid and thereby create "dynamic" filtering conditions.
It is a disadvantage in the case of instruments such as these that they are suitable only for use in the laboratory but not for example, outdoors in the area of protection of the environment. Without a strong rotating guide magnet, these pressure filtration cells would operate under "static" filtration conditions and would result in considerably less filtrating performance. Moreover, the customary cells depend on a compressed gas source which according to its nature is locally fixed.
In the case of the customary pressure filtration cells, furthermore, the partly very long stirrer shaft, especially in the case of larger cells, which require greater driving forces and thus coupling forces for the stirring mechanism, is disadvantageous. A fairly stable support and mounting of the small stirring rod is extremely costly.
The invention is based on the object of creating an apparatus of the initially mentioned type, which makes possible dynamic pressure filtration independent of the locale, i.e., it can be performed indoors or outdoors as well.
It is another object of the invention to provide a portable pressure filtration cell.
It is a further object of the invention to provide a pressure filtration cell having a hand-actuating, separably detachable pressurizing mechanism.